PostgreSQL performance scaling

Ivan Voras ivoras at
Tue Nov 23 02:15:34 UTC 2010

On 23 November 2010 10:35, David Xu <davidxu at> wrote:
> Ivan Voras wrote:

>> and the overall behaviour is similar - the processes spend a lot of time
>> in "sbwait" and "ksem" states.
> Strange, the POSIX semaphore in head branch does not use ksem, it is
> based on umtx, there is no limit on POSIX semaphore, the only limit
> is process's address space which limits how many semaphores can be
> used.

*shrug*; I don't know how it could be wrong - this PostgreSQL was
built from ports after I upgraded & booted 9-current.

If it didn't use POSIX semaphores from HEAD, shared semaphores
wouldn't have worked, right?

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